package dao;

import com.mysql.jdbc.Connection;
import model.Blog;
import util.DBUtil;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class BlogDao {
    //1.新增操作(提交博客)
    public void insert(Blog blog) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            //1.建立连接
            connection = DBUtil.getConnection();
            //2.构造sql
            String sql = "insert into blog values (null, ?, ?, now(), ?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1, blog.getTitle());
            statement.setString(2, blog.getContent());
            statement.setInt(3, blog.getUserId());
            statement.executeUpdate();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            DBUtil.close(connection, statement, null);
        }
    }

    //2.查询博客列表
    public List<Blog> getBlogs() {
        List<Blog> blogList = new ArrayList<>();
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from blog order by postTime desc";
            statement = connection.prepareStatement(sql);
            resultSet = statement.executeQuery();
            while (resultSet.next()) {
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                //此处读到的正文是整个文章的内容, 而博客列表页只希望显示一小部分
                String content = resultSet.getString("content");
                if(content.length() > 100) {
                    content = content.substring(0,100) + "...";
                }
                blog.setContent(content);

                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                blogList.add(blog);
            }
        }catch (SQLException e) {
            throw  new RuntimeException();
        }finally {
            DBUtil.close(connection,statement,null);
        }
        return blogList;
    }

    //3.根据博客ID查询指定博客
    public Blog getBlog(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId);
            resultSet = statement.executeQuery();
            //查询结果只有1条或0条
            if(resultSet.next()) {
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                blog.setContent(resultSet.getString("content"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                return blog;
            }
        }catch (SQLException e) {
            throw new RuntimeException();
        } finally{
            DBUtil.close(connection,statement, resultSet);
        }
        return null;
    }

    //4.根据博客id删除博客
    public void delete(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "delete from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId);
            statement.executeUpdate();
        }catch (SQLException e) {
            throw new RuntimeException();
        } finally{
            DBUtil.close(connection,statement, null);
        }
    }
}
